The invention concerns the welding of metal parts, in particular in the aeronautic field, and more particularly in that of gas turbine engines.
Welding of the TIG (Tungsten Inert Gas) type makes it possible to weld metal parts by means of an electric arc. TIG welding is an arc welding method with a non-fusible electrode.
Referring to FIG. 1, an electric arc 61 is created between a welding torch 60, of which the potential is negative, and a first metal part 1, of which the potential is positive. The first part 1 is in contact with a second part 2 to which it is to be welded. The welding torch 60 is brought close to the first part 1, the potential difference creating an electric arc 61. The energy provided by the arc raises the temperature of the parts 1,2 bringing about their local fusion and their welding as they cool. However, when the parts are very thick, penetration of heat may not be sufficient, preventing effective welding.
When the thickness is not constant, welding brings about a variation in the quality of the weld, it being possible for welding to be of a good quality overall on thin zones and, conversely poor quality on thick zones.
It is possible to increase the power of the arc in order to improve welding of thick zones. However, passing a welding torch, parameterized with a high power over a thin zone, may deform the part and cause too great a penetration of heat in said part. The part thus deformed cannot be repaired and thus must be rejected.